The present invention relates to improvements in apparatus for removing exposed photographic roll films from containers or cassettes of the type wherein the film is located in front of a backing strip and is expelled from the takeup section of the container in response to withdrawal of the backing strip through an exposure opening which is provided in an intermediate section or bridge of the container.
U.S. Pat. No. 3,921,878 to Zangenfeind discloses an apparatus wherein one end of the backing strip in the properly located container for exposed photographic roll film is expelled from the intermediate section via exposure opening in response to forward movement of a pivotable pusher which enters the intermediate section by way of a second opening serving to permit observation of indicia which are applied to the rear side of the backing strip in order to enable the user of a camera to ascertain the number of exposed or unexposed film frames. When the pusher performs a forward stroke, the one end of the backing strip is caused to enter the nip of two advancing rolls which are driven to draw the backing strip from the takeup section of the container whereby the leader of the film emerges from the exposure opening, is separated from the backing strip by a deflector and enters a channel to advance toward the nip of a second pair of driven advancing rolls which transport the film toward a further processing station, e.g., into the range of a splicing device which attaches the leader of the film to the trailing end of a preceding exposed film.
The apparatus which is disclosed in U.S. Pat. No. 4,004,724 to Zangenfeind et al. is designed to prevent the tendency of the exposed film to curl from interfacing with orderly transport of the film toward the next processing station. To this end, the apparatus of Zangenfeind et al. comprises means defining a relatively narrow film channel wherein the film advances from the exposure opening toward the respective advancing rolls or directly to the splicing station and a roll or an analogous device which is closely adjacent to the location where the leader of the film emerges from the bridge of the container to advance toward the inlet of the film channel. The roll prevents the leader of the film from advancing along a path other than toward and into the inlet of the film channel.
In the just described apparatus, the film is withdrawn in such a way that the film portion which extends between the takeup section and the exposure opening is substantially parallel to the rear wall of the aforementioned bridge, namely, to the wall which is formed with the observation opening. This is considered desirable and necessary in order to prevent the emulsion-coated surface of the film from rubbing against the edge of the bridge, namely, that edge which is nearest to the takeup section and bounds a portion of the exposure opening. The aforementioned roll in the apparatus of Zangenfeind et al. can be placed directly into the exposure opening so that it positively prevents any rubbing contact between the film and the edge bounding the exposure opening.
It has been found that the apparatus which are disclosed in the aforediscussed patents are ideally suited for withdrawal of exposed films from precision-finished containers and when the films are exposed in sophisticated cameras wherein the film transporting mechanism includes a clutch which prevents excessive tensioning of the film when the user of the camera attempts to advance the film upon completion of exposure of the last film frame. At the present time, the majority of roll films are exposed in inexpensive cameras with rudimentary film transporting mechanisms which do not embody a friction clutch or an analogous device capable of preventing complete extraction of the trailing end of the film from the supply section of the container or pronounced tensioning of the exposed film when the user attempts to advance the film under the aforementioned circumstances, i.e., upon completion of the last exposure. Moreover, all or nearly all containers for photographic roll film consist of synthetic plastic material whose components are welded together in response to the application of heat and/or pressure. The regions where the components of a mass-produced plastic container are welded together exhibit pronounced seams some of which are located in the interior of the container so that they interfere or are likely to interfere with predictable transport of the film, especially during withdrawal of exposed film through the exposure opening. In addition, the relative positions of components in fully assembled condition of a mass-produced plastic container deviate from optimum positions, often by as much as one-tenth or two-tenths of one millimeter. This, too, creates problems during withdrawal of exposed film through the exposure opening of a container. In many instances, a film which is exposed in an inexpensive camera wherein the film transporting mechanism does not embody a clutch or the like lies askew, i.e., it rubs against one flange of the bridge of the container. This is attributable, at least in part, to the fact that the containers are provided with tooth-like or toothed catches which engage one side of the trailing end of the film and cause at least some changes in orientation of the film when the latter is forcibly pulled by the transporting mechanism upon completion of exposure of the last film frame. The change of orientation may result in frictional engagement between the trailing portion of the film and a seam at the inner side of the bridge of the container; this further complicates the withdrawal of exposed film by way of the exposure opening. Therefore, when the film is to be withdrawn in apparatus of the type disclosed in the aforementioned patents to Zangenfeind and Zangenfeind et al., it is likely to cause breakage of the backing strip. Moreover, it happens quite frequently that exposed film which is stored in the takeup section finds its way to the rear side of the backing strip and cannot be introduced into the film channel. Still further, it can happen that the trailing portion of the exposed film changes its orientation to such an extent that it cannot be expelled via exposure opening in response to forward movement of the pusher because its frictional engagement with the adjacent component or components of the container is too strong.